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Biron, Éric

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Biron

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Éric

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Université Laval. Faculté de pharmacie

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ncf11849118

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Voici les éléments 1 - 10 sur 26
  • PublicationAccès libre
    Bacteriocins as a new generation of antimicrobials : toxicity aspects and regulations
    (Elsevier, 2020-09-02) Ben Said, Laila; Biron, Éric; Soltani, Samira; Gaudreau, Hélène; Fliss, Ismaïl; Bédard, François; Hammami, Riadh
    In recent decades, bacteriocins have received substantial attention as antimicrobial compounds. Although bacteriocins have been predominantly exploited as food preservatives, they are now receiving increased attention as potential clinical antimicrobials and as possible immune-modulating agents. Infections caused by antibiotic-resistant bacteria have been declared as a global threat to public health. Bacteriocins represent a potential solution to this worldwide threat due to their broad- or narrow-spectrum activity against antibiotic-resistant bacteria. Notably, despite their role in food safety as natural alternatives to chemical preservatives, nisin remains the only bacteriocin legally approved by regulatory agencies as a food preservative. Moreover, insufficient data on the safety and toxicity of bacteriocins represent a barrier against the more widespread use of bacteriocins by the food and medical industry. Here, we focus on the most recent trends relating to the application of bacteriocins, their toxicity and impacts.
  • PublicationAccès libre
    Recent progress in the chemical synthesis of class II and s-glycosylated bacteriocins
    (Frontiers Research Foundation, 2018-05-23) Biron, Éric; Bédard, François
    A wide variety of antimicrobial peptides produced by lactic acid bacteria (LAB) have been identified and studied in the last decades. Known as bacteriocins, these ribosomally synthesized peptides inhibit the growth of a wide range of bacterial species through numerous mechanisms and show a great variety of spectrum of activity. With their great potential as antimicrobial additives and alternatives to traditional antibiotics in food preservation and handling, animal production and in veterinary and medical medicine, the demand for bacteriocins is rapidly increasing. Bacteriocins are most often produced by fermentation but, in several cases, the low isolated yields and difficulties associated with their purification seriously limit their use on a large scale. Chemical synthesis has been proposed for their production and recent advances in peptide synthesis methodologies have allowed the preparation of several bacteriocins. Moreover, the significant cost reduction for peptide synthesis reagents and building blocks has made chemical synthesis of bacteriocins more attractive and competitive. From a protein engineering point of view, the chemical approach offers many advantages such as the possibility to rapidly perform amino acid substitution, use unnatural or modified residues, and make backbone and side chain modifications to improve potency, modify the activity spectrum or increase the stability of the targeted bacteriocin. This review summarized synthetic approaches that have been developed and used in recent years to allow the preparation of class IIa bacteriocins and S-linked glycopeptides from LAB. Synthetic strategies such as the use of pseudoprolines, backbone protecting groups, microwave irradiations, selective disulfide bridge formation and chemical ligations to prepare class II and S-glycosylsated bacteriocins are discussed.
  • PublicationAccès libre
    Bacteriocin-based synergetic consortia : a promising strategy to enhance antimicrobial activity and broaden the spectrum of inhibition
    (ASM Press, 2022-02-16) Ben Said, Laila; Biron, Éric; Soltani, Samira; Fliss, Ismaïl; Subirade, Muriel
    Bacteria-derived natural antimicrobial compounds such as bacteriocins, reruterin, and organic acids have recently received substantial attention as food preservatives or therapeutic alternatives in human or animal sectors. This study aimed to evaluate the antimicrobial activity of different bacteria-derived antimicrobials, alone or in combination, against a large panel of Gram-negative and Gram-positive bacteria. Bacteriocins, including microcin J25, pediocin PA-1, nisin Z, and reuterin, were investigated alone or in combination with lactic acid and citric acid, using a checkerboard assay. Concentrations were selected based on predetermined MICs against Salmonella enterica subsp. enterica serovar Newport ATCC 6962 and Listeria ivanovii HPB28 as Gram-negative and Gram-positive indicator strains, respectively. The results demonstrated that the combination of microcin J25 + citric acid + lactic acid; microcin J25 + reuterin + citric acid; and microcin J25 + reuterin + lactic acid tested against S. Newport ATCC 6962 showed synergistic effects (FIC index = 0.5). Moreover, a combination of pediocin PA-1 + citric acid + lactic acid; and reuterin + citric acid + lactic acid against L. ivanovii HPB28 showed a partially synergistic interactions (FIC index = 0.75). Nisin Z exerted a partially synergistic effect in combination with acids (FIC index = 0.625 -0.75), whereas when it was combined with reuterin or pediocin PA-1, it showed additive effects (FIC index = 1) against L. ivanovii HPB28. The inhibitory activity of synergetic consortia were tested against a large panel of Gram-positive and Gram-negative bacteria. According to our results, combining different antimicrobials with different mechanisms of action led to higher potency and a broad spectrum of inhibition, including multidrug-resistance pathogens.
  • PublicationAccès libre
    Convenient two-step synthesis of highly functionalized benzo-fused 1,4-diazepin-3-ones and 1,5-diazocin-4-ones by sequential Ugi and intramolecular SNAr reactions
    (Pergamon Press, 2017-09-18) Biron, Éric; Vézina-Dawod, Simon; Liang, Xinxia; Gerber, Nicolas
    Benzodiazepinones are an important family of heterocycles with very attractive pharmacological properties and peptidomimetic abilities. We report herein a rapid and efficient two-step synthesis of polysubstituted 1,4-benzodiazepin-3-ones and 1,5-benzodiazocin-4-ones using a multicomponent condensation/cyclization strategy. The approach uses an Ugi four-component reaction to condense readily available Nα-Fmoc-amino acids, amines and isocyanides with a 2-fluorobenzaldehyde derivative followed by a one-pot Fmoc-group removal, intramolecular aromatic nucleophilic substitution for ring closure and side chain deprotection. The described method gives access to benzo-fused 7- and 8-membered rings bearing a wide variety of functionalized substituents and was applied to efficiently prepare tri- and tetrasubstituted 1,4-benzodiazepin-3-ones and 1,5-benzodiazocin-4-ones in high yields in two straightforward steps.
  • PublicationAccès libre
    Synthesis, antimicrobial activity and conformational analysis of the class IIa bacteriocin pediocin PA-1 and analogs thereof
    (Springer Nature, 2018-06-13) Biron, Éric; Fliss, Ismaïl; Bédard, François; Rebuffat, Sylvie; Menétrey, Séverine; Hammami, Riadh
    The antimicrobial peptide pediocin PA-1 is a class IIa bacteriocin that inhibits several clinically relevant pathogens including Listeria spp. Here we report the synthesis and characterization of whole pediocin PA-1 and novel analogs thereof using a combination of solid- and solution-phase strategies to overcome difficulties due to instability and undesired reactions. Pediocin PA-1 thus synthesized was a potent inhibitor of Listeria monocytogenes (MIC = 6.8 nM), similar to the bacteriocin produced naturally by Pediococcus acidilactici. Of particular interest is that linear analogs lacking both of the disulfide bridges characterizing pediocin PA-1 were as potent. One linear analog was also a strong inhibitor of Clostridium perfringens, another important food-borne pathogen. These results are discussed in light of conformational information derived from circular dichroism, solution NMR spectroscopy and structure-activity relationship studies.
  • PublicationAccès libre
    In vitro investigation of gastrointestinal stability and toxicity of 3-hyrdoxypropionaldehyde (reuterin) produced by Lactobacillus reuteri
    (Elsevier, 2021-03-31) Soltani, Samira; Couture, Frédéric; Boutin, Yvan.; Ben Said, Laila; Cashman-Kadri, Samuel; Subirade, Muriel; Biron, Éric; Fliss, Ismaïl
    Reuterin (3-hyrdoxypropionaldehyde (3-HPA)) is a highly potent metabolite of L. reuteri, which has applications in food, health, and veterinary sectors. Similar to other natural antimicrobial compounds, the approval of reuterin as a bio-preservative or therapeutic agent by regulatory agencies relies on sufficient data on its cytotoxicity and behavior in the gastrointestinal environment. Although the antimicrobial activity of reuterin has been broadly studied, its safety and toxicity are yet to be explored in detail. In this study, the stability and activity of reuterin were investigated in the gastrointestinal tract using in vitro models simulating gastrointestinal conditions. In addition, hemolytic activity and in vitro cytotoxicity of reuterin were evaluated by neutral red assay and lactate dehydrogenase (LDH) colorimetric assay using the same cell line. Activity of reuterin was observed to be stable during gastrointestinal transit. Viability and membrane integrity of cells remained unaltered by reuterin up to 1080 mM concentration. Furthermore, no hemolysis was observed in blood cells exposed to 270 mM reuterin. This study provides unique and highly relevant in vitro data regarding gastrointestinal behavior and toxicity of reuterin. In conclusion, the current study indicates that within a certain concentration range, reuterin can be safely used in bio-preservation and therapeutics applications. However, further in vivo studies are required to confirm these findings.
  • PublicationAccès libre
    The gliotransmitter ACBP controls feeding and energy homeostasis via the melanocortin system
    (American Society for Clinical Investigation, 2019-04-02) Bouyakdan, Khalil; Biron, Éric; Martin, Hugo; Liénard, Fabienne; Budry, Lionel; Taib, Bouchra; Rodaros, Demetra; Chrétien, Chloé; Husson, Zoé; Cota, Daniela; Pénicaud, Luc; Fulton, Stephanie; Fioramonti, Xavier; Alquier, Thierry
    Glial cells have emerged as key players in the central control of energy balance and etiology of obesity. Astrocytes play a central role in neural communication via the release of gliotransmitters. Acyl-CoA–binding protein–derived (ACBP-derived) endozepines are secreted peptides that modulate the GABAA receptor. In the hypothalamus, ACBP is enriched in arcuate nucleus (ARC) astrocytes, ependymocytes, and tanycytes. Central administration of the endozepine octadecaneuropeptide (ODN) reduces feeding and improves glucose tolerance, yet the contribution of endogenous ACBP in energy homeostasis is unknown. We demonstrated that ACBP deletion in GFAP+ astrocytes, but not in Nkx2.1-lineage neural cells, promoted diet-induced hyperphagia and obesity in both male and female mice, an effect prevented by viral rescue of ACBP in ARC astrocytes. ACBP+ astrocytes were observed in apposition with proopiomelanocortin (POMC) neurons, and ODN selectively activated POMC neurons through the ODN GPCR but not GABAA, and suppressed feeding while increasing carbohydrate utilization via the melanocortin system. Similarly, ACBP overexpression in ARC astrocytes reduced feeding and weight gain. Finally, the ODN GPCR agonist decreased feeding and promoted weight loss in ob/ob mice. These findings uncover ACBP as an ARC gliopeptide playing a key role in energy balance control and exerting strong anorectic effects via the central melanocortin system.
  • PublicationAccès libre
    Synthesis and biological evaluation of novel 1,4-benzodiazepin-3-one derivatives as potential antitumor agents against prostate cancer
    (Pergamon, 2021-07-21) Biron, Éric; Gobeil, Stéphane; Vézina-Dawod, Simon; Gerber, Nicolas; Guay, Louis-David; Perreault, Martin
    A novel tumor suppressing agent was discovered against PC-3 prostate cancer cells from the screening of a 1,4-benzodiazepin-3-one library. In this study, 96 highly diversified 2,4,5- trisubstituted 1,4-benzodiazepin-3-one derivatives were prepared by a two-step approach using sequential Ugi multicomponent reaction and simultaneous deprotection and cyclization to afford pure compounds bearing a wide variety of substituents. The most promising compound showed a potent and selective antiproliferative activity against prostate cancer cell line PC-3 (GI₅₀ = 10.2 µM), but had no effect on LNCAP, LAPC4 and DU145 cell lines. The compound was initially prepared as a mixture of two diastereomers and after their separation by HPLC, similar antiproliferative activities against PC-3 cells were observed for both diastereomers (2S,5S: GI₅₀ = 10.8 µM and 2S,5R: GI₅₀ = 7.0 µM). Additionally, both diastereomers showed comparable stability profiles after incubation with human liver microsomes. Finally, in vivo evaluation of the hit compound with the chick chorioallantoïc membrane xenograft assay revealed a good toxicity profile and significant antitumor activity after intravenous injection.
  • PublicationRestreint
    Synthetic Strategies for Macrocyclic Peptides
    (John Wiley & Sons, 2017-08-18) Biron, Éric; Vézina-Dawod, Simon; Bédard, François
    Peptide macrocycles form an outstanding class of natural and synthetic bioactive compounds. This chapter discusses synthetic strategies for the final ring‐closing reaction by the widely employed and versatile processes of lactamization, lactonization, and disulfide bridge formation. According to the nature of the chemical bond found in the backbone, cyclic peptides can be classified in two major categories: homodetic peptides and heterodetic peptides. In principle, all methods suitable for peptide bond formation can be applied for head‐to‐tail macrocyclization of linear peptides; however the reaction usually proceeds more slowly than the corresponding bimolecular version. During synthesis design, the C‐terminal amino acid of the linear precursor and the coupling reagent should be carefully chosen to minimize epimerization at the C‐terminal residue during cyclization. In many cases, the solution‐phase strategy is the best choice for performing the macrocyclization step, especially when larger quantities of cyclic peptide are required.
  • PublicationAccès libre
    In vitro assessment of skin sensitization, irritability and toxicity of bacteriocins and reuterin for possible topical applications
    (Nature Publishing Group, 2022-03-17) Biron, Éric; Frédéric Couture; Soltani, Samira; Fliss, Ismaïl; Subirade, Muriel; Boutin, Yvan.
    Bacteriocins and reuterin are promising antimicrobials for application in food, veterinary, and medical sectors. In the light of their high potential for application in hand sanitizer, we investigated the skin toxicity of reuterin, microcin J25, pediocin PA-1, bactofencin A, and nisin Z in vitro using neutral red and LDH release assays on NHEK cells. We determined their skin sensitization potential using the human cell line activation test (h-CLAT). Their skin irritation potential was measured on human epidermal model EpiDerm™. We showed that the viability and membrane integrity of NHEK cells remained unaltered after exposure to bacteriocins and reuterin at concentrations up to 400 µg/mL and 80 mg/mL, respectively. Furthermore, microcin J25 and reuterin showed no skin sensitization at concentrations up to 100 µg/mL and 40 mg/mL, respectively, while pediocin PA-1, bactofencin A, and nisin Z caused sensitization at concentrations higher than 100 µg/mL. Tissue viability was unafected in presence of bacteriocins and reuterin at concentrations up to 200 µg/mL and 40 mg/ mL, respectively, which was confrmed by measuring cytokine IL-1α and IL-8 levels and by histological analysis. In conclusion, the current study provides scientifc evidence that some bacteriocins and reuterin, could be safely applied topically as sanitizers at recommended concentrations